1. Field of the Invention
The present invention relates to a paste-like polymerizable composition in which two or three pastes are intimately mixed with each other to polymerize, the pastes do not gel and their polymerization curing times being stable, even when the pastes before the polymerization are preserved for a long period of time. The paste-like polymerizable composition of the present invention can be used for various industrial adhesives and molding resins, and one of its suitable applications is a dental application, especially for dental adhesives. More specifically, the present invention relates to a paste-like polymerizable composition containing a ternary catalyst comprised of a pyrimidinetrione derivative, an organic halide, and an organometallic compound.
2. Description of the Conventional Art
As means for polymerizing a paste-like composition containing a radical polymerizable monomer at an ambient temperature, there has been old employed means for using a combination of an organic peroxide and an aromatic tertiary amine as a chemical polymerization catalyst. In this means, by not only adjusting the amounts of the organic peroxide and the aromatic tertiary amine to be compounded in the paste-like composition but also using a polymerization inhibitor in combination, the polymerization curing time is regulated, and the storage stability of the paste-like composition before the polymerization is enhanced. However, since the organic peroxide is an unstable substance having a half-life, when a large amount of the organic peroxide is compounded in the paste-like composition in order to accelerate the polymerization curing time, the paste-like composition per se is liable to form a gel before the polymerization in the case of preservation over a long period of time. Conversely, when a large amount of the polymerization inhibitor is compounded in the paste-like composition in order to ensure the storage stability over a long period of time, there is involved a problem that the polymerization curing time becomes extremely long. Accordingly, a measure for preserving the paste-like composition under refrigeration to delay the half-life of the organic peroxide had to be taken
In addition, polymerization means using oxidation of a trialkylborane is known. But, since the trialkylborane is very easily oxidized, it is impossible to compound it into a radical polymerizable monomer-containing paste-like composition. Accordingly, the trialkylborane must be preserved in a container separately from the monomer and added to the paste-like composition during the use, resulting in that the preservation is laborious and the operation is complicated.
The present invention is aimed to overcome the above-described problems of the conventional art and to provide a paste-like polymerizable composition in which two or three pastes are intimately mixed with each other to polymerize, the pastes do not gel and their polymerization curing times being stable, even when the pastes before the polymerization are preserved for a long period of time.
In order to achieve the above-described aim, I, the present inventor made extensive and intensive investigations. As a result, it has been found that, when, as polymerization means of a polymerizable composition comprised of (a) a (meth)acrylate having at least one unsaturated double bond and (b) a filler as major components, a ternary catalyst comprising (c) a pyrimidinetrione derivative, (d) an organic halide, and (e) an organometallic compound is used, the ternary catalyst does not have a half-life, and hence, even in the case of preservation over a long period of time, the polymerization curing time is stable, leading to accomplishment of the present invention.
Specifically, the invention is concerned with a paste-like polymerizable composition comprising a first paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (c) a pyrimidinetrione derivative; and a second paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler, (d) an organic halide and (e) an organometallic compound, or a third paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (d) an organic halide and a fourth paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (e) an organometallic compound. When the filler as the component (b) is one or two or more members selected from anhydrated silica, hydrated silica, hydrated calcium silicate, and hydrated aluminum silicate, even in the case of preservation over a long period of time, the paste-like polymerizable composition before the polymerization does not gel, and hence, such is preferred.
In the paste-like polymerizable composition according to the present invention, examples of the (meth)acrylate having at least one unsaturated double bond as the component (a) that is used for the respective pastes include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxy-1,3-di(meth)acryloxypropane, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polybutylene glycol di(meth)acrylate, and bisphenol A diglycidyl (meth)acrylate. Further, examples of (meth)acrylates having a urethane bond include di-2-(meth)acryloxyethyl-2,2,4-trimethylhexa-methylene dicarbamate and 1,3,5-tris[1,3-bis{(meth)-acryloyloxy)-2-propoxycarbonylaminohexane]-1,3,5-(1H,3H,5H) triazin-2,4,6-trione. Besides, there are exemplified a (meth)acrylate of a urethane oligomer comprising 2,2xe2x80x2-di(4-hydroxycyclohexyl)propane, 2-oxypanone, hexamethylene diisocyanate and 2-hydroxyethyl (meth)acrylate and a (meth)acrylate of a urethane oligomer comprising 1,3-butanediol, hexamethylene diisocyanate and 2-hydroxyethyl (meth)acrylate. These (meth)acrylates may be used alone or in admixture of two or more thereof. Of these, are particularly preferred tetrahydrofurfuryl (meth)arylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxy-1,3-di(meth)acrylate, because they well dissolve the pyrimidinetrione derivative and the organic halide therein.
In the paste-like polymerizable composition according to the present invention, examples of the filler as the component (b) that is used for the respective pastes are powders of anhydrated silica, glasses such as barium glass, alumina glass, potassium glass, and fluoroaluminosilicate glass, synthetic zeolite, calcium phosphate, feldspar, fumed silica, aluminum silicate, calcium silicate, magnesium carbonate, hydrated silica, hydrated calcium silicate, hydrated aluminum silicate, and quartz. These fillers may be subjected to a surface treatment with, e.g., xcex3-methacryloxypropyl trimethoxysilane, vinyl trichlorosilane, vinyl triethoxysilane, vinyl trimethoxysilane, vinyl triacetoxysilane, vinyl tri(methoxyethoxy)silane. Further, are employable organic-inorganic composite fillers prepared by mixing the foregoing filler with a polymerizable monomer or oligomer, curing the mixture and then pulverizing the cured mixture. These fillers may be used alone or in admixture of two or more thereof. Of these, are preferred anhydrated silica, hydrated silica, hydrated calcium silicate, and hydrated aluminum silicate, because, even in the case of preservation over a long period of time, they have an effect for preventing the paste-like polymerizable composition before polymerization from gelling. Incidentally, as a matter of course, with respect to the components (a) and (b) to be used in the present invention, different substances may be used for the respective pastes.
In the paste-like polymerizable composition according to the present invention, examples of the pyrimidinetrione derivative as the component (c) that is used for the first paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (c) a pyrimidinetrione derivative include 1-benzyl-5-phenyl-pyrimidinetrione, 1-cyclohexyl-5-ethyl-pyrimidinetrione, 1,3-dimethyl-5- cyclopentyl-pyrimidinetrione, 1,3- dimethyl-5-cyclohexyl-pyrimidinetrione, 1,3- dimethyl-5-ethyl-pyrimidinetrione, 1,3-dimethyl-5- isobutyl-pyrimidinetrione, 1,3-dimethyl-5- phenyl-pyrimidinetrione, 1,3-dimethyl-5-n-butyl- pyrimidinetrione, 1,5-dimethyl-pyrimidinetrione, 5-n-butyl-pyrimidinetrione, 5-cyclohexyl-pyrimidinetrione, 5-ethyl-pyrimidinetrione, 5-isobutyl-pyrimidinetrione, 5-isopropyl-pyrimidinetrione, 5-phenylpyrimidinetrione, and 1,3,5-trimethyl-pyrimidinetrione. These pyrimidinetrione derivatives may be used alone or in admixture of two or more thereof. A suitable amount of the pyrimidinetrione derivative as the component (c) is 0.05 to 5 parts by weight based on 100 parts by weight of the total sum of the (meth)acrylate having at least one unsaturated double bond as the component (a) and the filler as the component (b) in the first paste.
In the paste-like polymerizable composition according to the present invention, examples of the organic halide as the component (d) that is used for other paste(s) than the first paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (c) a pyrimidinetrione derivative include benzyltributylammonium chloride, benzyldimethylcetylammonium chloride, benzyl-dimethylsteaxylammonium chloride, benzyltriethyl-ammonium bromide, benzyltrimethylammonium chloride, cetalkonium chloride, cetylpyridinium bromide, cetylpyridinium chloride, cetyltriethylammonium bromide, didecyldimethylammonium chloride, dilauryldimethylammonium chloride, domiphen bromide, lauryldimethylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, tetra-n-butyl ammonium iodide, tetradecyltrimethylammonium bromide, tetraethylammonium bromide, tetraethylammonium iodide, and trioctylmethylammonium chloride. These organic halides may be used alone or in admixture of two or more thereof. A suitable amount of the organic halide as the component (d) is 0.05 to 5 parts by weight based on 100 parts by weight of the total sum of the (meth)acrylate having at least one unsaturated double bond as the component (a) and the filler as the component (b) in the paste other than the first paste.
In the paste-like polymerizable composition according to the present invention, examples of the organometallic compound as the component (e) that is used for other paste(s) than the first paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (c) a pyrimidinetrione derivative include acetylacetone copper, copper 4-cyclohexylbutyrate, cupric acetate, copper oleate, acetylacetone manganese, manganese naphthenate, manganese octylate, acetylacetone cobalt, cobalt naphthenate, acetylacetone lithium, lithium acetate, acetylacetone zinc, zinc naphthenate, acetylacetone nickel, nickel acetate, acetylacetone aluminum, acetylacetone calcium, acetylacetone chromium, acetylacetone iron, sodium naphthenate, and rare earth octoate. These organometallic compounds may be used alone or in admixture of two or more thereof. A suitable amount of the organometallic compound as the component (e) is 0.0001 to 0.1 parts by weight based on 100 parts by weight of the total sum of the (meth)acrylate having at least one unsaturated double bond as the component (a) and the filler as the component (b) in the paste other than the first paste.
In the paste-like polymerizable composition according to the present invention, with respect to the organic halide as the component (d) and the organometallic compound as the component (e) to be used for other paste(s) than the first paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (c) a pyrimidinetrione derivative, there are the case where they are compounded in one paste as in the second paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler, (d) an organic halide and (e) an organometallic compound; and the case where they are separately compounded in two pastes as in the third paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (d) an organic halide and the fourth paste comprising (a) a (meth)acrylate having at least one unsaturated double bond, (b) a filler and (e) an organometallic compound.
This is because, when the organic halide as the component (d) or the organometallic compound as the component (e) is simultaneously compounded in the first paste having the pyrimidinetrione derivative as the component (c) compounded therein, radicals are generated at an ambient temperature in the first paste, whereby the polymerization is initiated.
It is possible to further compound a photopolymerization type polymerization initiator in the paste-like polymerizable composition according to the present invention and irradiate the mixture with light such as ultraviolet light and visible lights, thereby initiating the polymerization. During this operation, as a light source, are employable various mercury vapor lamps of super high pressure, high pressure, medium pressure and low pressure, a chemical lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a xenon lamp, and an argon ion laser A suitable compounding amount of the photopolymerization type polymerization initiator is 0.01 to 5 parts by weight based on 100 parts by weight of the total sum of the (meth)acrylate having at least one unsaturated double bond as the component (a) and the filler as the component (b).
To the paste-like polymerizable composition according to the present invention, can be added various components other than those as described above, such as organic solvents, polymerization inhibitors, antioxidants, ultraviolet light absorbers, and pigments, it desired in practical use.